Labour and Social Services Minister Paurina Mpariwa said that the number of those in need is expected to rise in the next few months if the country continues to experience poor rains.
"These people require urgent food aid to avert disaster," Mpariwa said.
The government's official food reserve institution, the Grain Marketing Board, is working to find ways to help the vulnerable, she said.
Other initiatives include food-for-work schemes, in which people are given food in exchange for working on government projects.
The Zimbabwe Vulnerability Assessment Committee (ZimVac) said that, by the end of last year, the reported number of people in need of assistance had increased by 60%.
The World Food Programme (WFP) and other aid partners are planning to intensify their operations.
"Food security prospects for Zimbabwe for 2012-2013 are the worst in three years. During the peak hunger period of January to March 2013, some 1.7-million will be in a condition of food insecurity, a significant increase from 1.3-million last year," said the WFP.
"This [figure] represents some 19% of the rural population. The worst affected areas are Matabeleland North and South and Masvingo."
The body attributed the situation to lower agricultural production, with late rains, prolonged dry spells and poor access to crop inputs leading to cereal production dropping by a third.
It said government efforts are having little effect owing to low coverage of its grain loan scheme.
It added that WFP assistance to poor and vulnerable households between October 2012 and March 2013 is expected to ease cereal shortages in drought-hit areas, but food prices are also expected to rise as the lean season approaches.
"Below-normal rainfall is forecast for the southern regions of Zimbabwe throughout the coming season, which may aggravate conditions in regions hit by last season's drought," said the WFP.